| 摘要 |
PURPOSE:To improve the brightness of a viewfinder and the light utilization efficiency of automatic focusing by using two beam splitters which have specific optical characteristics. CONSTITUTION:Subject reflected light passed through a zoom photographic lens 1 is split into two by a beam splitter 1 which has equal reflectivity and transmissivity to visible light and reflects infrared light completely, and the reflected light becomes photographic light. Transmitted light, on the other hand, is split by a beam splitter 6 which transmits infrared light completely and reflects visible light completely; the transmitted light is light for automatic focusing and the reflected light is light to viewfinder. Thus, the brightness of the viewfinder and the light utilization efficiency of automatic focusing are improved by the simple constitution which uses the two beam splitters. |
